Variability in water vapor is more spatial than temporal. The Bay of Bengal has values of W consistently higher than the rest of the IO, reaching over 60 kg/m^2 for the months of June, July, August and Septemper. While the Arabian Sea above 15N has less than 30 kg/m^2 for the months November thru April. For the complimentary period of May thru October south of ~18S W is always below 30 kg/m^2.
Click here to see an animated movie of water vapor data.